Upss, my bad. Sorry. I'm used to so many generalized how do I get this look threads that I skipped reading the title properly.

Basically if you want to get this in post simply apply motion blur filter. If you want to be specific use masks. For example select using color range only reds or only blue or what every you prefer for your specific image and apply the motion blur filter. It's in simple looking plain background so you don't have to worry about blurring other elements in the background that you sometimes what to avoid.

Krunoslav-Stifter wrote: If you want to be specific use masks. For example select using color range only reds or only blue or what every you prefer for your specific image and apply the motion blur filter.

I'm not sure to follow you : you mean applying the blur filter on, say, only the RED channel ?

I'm not sure to follow you : you mean applying the blur filter on, say, only the RED channel ?

No not necessary, often times it will give you less controled results. Use color range command for example. Now you can do this in tow ways.

First one is to use color range to sample the colors you want to blur, say red for example. Than you CRTL/Command + J copy the selection to the new layer and apply motion blur.

Second way to do it is much more flexible. Turn background layer to smart filter. use Color range like you would in the first example and select the colors you want to blur. Than with selection active you simply apply motion blur and it will be added to the smart filer mask. So you can now modify the mask as you wish and since it's applied as smart filter you can change the settings of the motion blur filter at any time as you see fit.

No not necessary, often times it will give you less controled results. Use color range command for example. Now you can do this in tow ways.

First one is to use color range to sample the colors you want to blur, say red for example. Than you CRTL/Command + J copy the selection to the new layer and apply motion blur.

Second way to do it is much more flexible. Turn background layer to smart filter. use Color range like you would in the first example and select the colors you want to blur. Than with selection active you simply apply motion blur and it will be added to the smart filer mask. So you can now modify the mask as you wish and since it's applied as smart filter you can change the settings of the motion blur filter at any time as you see fit.

Krunoslav-Stifter wrote: First one is to use color range to sample the colors you want to blur, say red for example. Than you CRTL/Command + J copy the selection to the new layer and apply motion blur.

Second way to do it is much more flexible. Turn background layer to smart filter. use Color range like you would in the first example and select the colors you want to blur. Than with selection active you simply apply motion blur and it will be added to the smart filer mask. So you can now modify the mask as you wish and since it's applied as smart filter you can change the settings of the motion blur filter at any time as you see fit.

One disadvantage to the second method: Even with a selection active, motion blur will affect the entire image (behind the smart mask). When you alter the mask to expand the blur beyond the original selection, that will pull in blurred colors that weren't originally selected, muddying up the reds in this example (below).

If the aim is to blur specific colors, method 1 seems to work better. To preserve flexibility, make the copied selection a smart object, then blur. (To further enhance the blurred color, you can duplicate the blurred layer and shift the duplicate left or right.)

Using GIMP:
0. Duplicate the image to a new layer.
1. Increase the top layer's saturation.
2. Apply motion blur to the top layer.
3. Set top layer mode to Hard Light.
4. Mask out regions where you don't want the motion blur.